Helical retarding element.



J. E. FULWEILER.

HELICAL RETARDING ELEMENT.

APPLICATION F R. 19.191].

1,246,583. Patented Nov. 13, 1917.

UNITED STATES PATENT OFFICE.

JOHN EDWIN FULWEILER, 0F PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO LUTHER D. LOVEKIN, 0F PHILADELPHIA, PENNSYLVANIA.

HELICAL RETARDING ELEMENT.

Specification of Letters Patent. I Patented NO 13, 1917.

Application filed December 12, 1914, Serial No. 876,993. Renewed April 19, 1917. Serial No. 163,309.

To all whom it may concern:

Be it known that I, JOHN EDWIN FUL- WEILER, a citizen of the United States, residing in Philadelphia, in the county of Philadelphia and State of Pennsylvania, have invented certain new and useful Improvements in Helical Retarding Elements, of which the following is a true and exact description, reference being had to the accompanying drawings, which form a part thereof.

My present invention is a novel article of manufacture, consisting of a transversely corrugated metal ribbon twisted into a helix about an axis corresponding more or less exactly with the longitudinal median line of the ribbon. This article is adapted for various uses; but was primarily devised by me for use in heat interchanging apparatus, as a means for elongating the path of 'flow through a flue or conduit of a fluid absorbing or giving up heat as it passes through said conduit.

A device for this general purpose has heretofore been made by twisting a flat metallic ribbon into a helix; but I have found it to be difl'icult, and indeed practically impossible, to twist a ribbon of the desired dimensions into a helix with as fine a pitch as is frequently desirable. A flat ribbon of the desired width can be twisted into a helix of the desired pitch, only when the ribbon is substantially thicker than would be otherwise necessary. The added weight of material entailed by the extra thickness is, of course, undesirable. I have discovered, however, that after first transversely corrugating it, I may easily twist a ribbon of the desired width and thickness into a helix of as fine a pitch as is desired in practice.

The transverse corrugations may extend from one side edge of the ribbon to the other, or may be shorter corrugations extending into the ribbon from each side edge to or adjacent the center of the ribbon. The transverse corrugations of the ribbon are, in general, advantageous, when the new article of manufacture is used in heat interchanging apparatus, as set forth above, from the fact that the corrugations break up or prevent the formation of continuous stream lines of the fluid thermal agent flowing along the helix and thereby add materially to the rate at which heat is absorbed.

or given up by the fluid.

For a better understanding of the invention, reference should be had to the accompanying drawings and descriptive matter, in which I have illustrated and described preferred embodiments of the invention, and a use to which the new article of manufacture may advantageously be put.

Of the drawings:

Figure 1 is a perspective view of a preferred embodiment of my present invention;

Fig. 2 is a plan view; and Fig. 3 a side elevation, of the corrugated strip from which the article shown in Fig. 1 may be formed by a simple twisting operation;

Fig. 4 is a plan view of a blank transversely corrugated in a manner different from that in which the blank of Figs. 2 and 3 is corrugated;

Fig. 5 is a plan view of a blank transveisely corrugated in still another manner; an

Fig. 6 is a sectional elevation of a gas fired water heater in which my spiral flow producer is employed.

Fig. 1 of the drawings shows a preferred form of my novel helically twisted transversely corrugated metal ribbon. The finished article A of Fig. 1 may be produced from the plain transversely corrugated blank a ofFigs. 2 and 3, by twisting this blank about an axis corresponding more or less exactly with the longitudinal center line of the blank. The blank shown in Figs. 2 and 3 is uniformly fluted, so to speak, the corrugations extending from one side edge of the blank to the other, and each being uniform in transverse section from one end to the other. When a blank corrugated in this manner is subsequently twisted into a helix, there is a tendency to flatten the corrugations at the side edges of the ribbon, and a tendency to deepen the corrugations adjacent the longitudinal center line of the ribbon. Neither the corrugating of the ribbon to produce the blank of Figs. 2 or 3, nor the twisting of the corrugated blank of Figs. 2 and 3 into the helix of Fig. 1, necessarily involves, however, any material stretching or upsetting of any portion of the ribbon, such as necessarily occurs when a flat ribbon is twisted'into a helix in order to obtain the necessary increase in the length of the-side edges of the ribbon as compared with the median length of line of the helix.

be made outof sheet steel, one-thirty-second the ribbon. The article shown in Fig. 1 may thus be readily produced without any appreciable tendency of the ribbon to tear or buckle.

Instead of forming the blank initially with transverse corrugations extending uniformly from one side edge of the ribbon to the other, as shown in Figs. 2 and 3, the blank may be formed with corrugations extending from each side edge of the ribbon to, or adjacent to, the center line of the ribbon. These corrugations may be tapered, as in the blank AA shown in Fig. 4; or may be uniform in cross section, as in the blank AB shown in Fig. 5. The production of the blanks shown in Figs. 4 and 5, involves a stretching of the side edges of the blanks, but this stretching may be carried out rapidly and uniformly in the corrugating apparatus, and without resulting in any tendency to tear or distort the blanks.

In the apparatus shown in Fig. 6, for the purpose of illustrating one of the many uses to which my transversely corrugated, helically twisted ribbon may advantageously be put, B represents the tubular shell of a water heater for domestic use. This waterheater is of the general type disclosed and claimed in the application of Luther D. Lovekin, Ser. No. 733,033, filed Nov. 23, 1912. Am'ally disposed in the shell B is a tubular member comprising an enlarged lower portion C, and a spirally corrugated upper portion D. The enlarged lower portion C serves as the combustion chamber proper for the gas issuing from the gas burner E, and the hot products of combustion pass out of the combustion chamber through the spirally corrugated flue portion D. To elongate the path of flow of the products of combustion through the flue portion D, I employ such a helically twisted, transversely corrugated member A, as is shown in Fig. 1. In the use illustrated in Fig. 6, the ribbon out of which the member A is formed will ordinarily be at least two and one-half inches wide, and I have found that it is ordinarily advantageous to have the pitch of the helix such that there will be about one and one-half or two complete turns of the helix to each foot of axial length of Advantageously, the ribbon may of an inch in thickness or thereabout, and I have found it impossible to twist ordinary transversely metallic ribbon of the thickness and width mentioned into a helix of the relativelyhigh pitch specified; but when the ribbon is first transversely corrugated, as set forth herein, the twisting of the corrugated ribbon into a helix is a simple matter. The transverse corrugations of the member A are an advantage, when the member is used as shown in Fig.6, from the fact that they aid materially in agitating the products of combustion, and in preventing them from following continuous spiral stream lines in their passage through the flue D. This constant stirring, so to speak, adds appreciably to the rate at which the hot products of combustion give up their heat to the water in the shell A.

Another use to which my invention may be put with special advantage, is in the combustion fines of oil fired Scotch boilers. Helically twisted flow path elongating ribbons have heretofore been used in such a boiler, but it has not heretofore been possible in practice to obtain more than one complete turn of the flat ribbon helix employed for each two feet of axial length, whereas, with my improved device, two complete turns for each foot of axial length may readily be obtained. and this adds greatly to the eflectiveness of the twisted elements. v

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. As a new article of manufacture, a corrugated metallic ribbon twisted into a helix the axis of which lies between the side edges of the ribbon.

2. As a new article of manufacture, a helix formed by twisting a metallic ribbon having uniform transverse corrugations extending from one side edge of the ribbon to the other into a helix the axis of which lies midway between the side edges of the ribbon.

3. The combination with a flue or conduit of heat interchanging apparatus, of a helically twisted metallic flow retarding ribbon mounted therein, said ribbon being transversely corrugated and having the axis of the helix into which the ribbon is twisted between the side edges of the ribbon.

JOHN EDWIN FULW'EILER.

Witnesses:

ROMIIALD T. MGDONNELL, EMMZA S. Fwnwmmza. 

